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Linaro Introduces "Boottime" For Linux Kernel

Phoronix: Linaro Introduces "Boottime" For Linux Kernel

Up to this point if you have wanted to monitor the start-up/boot performance of a Linux system, namely how long it takes the Linux kernel to boot, you have had to use an independent utility like Bootchart. Now with work done by the Linaro project, there is an in-kernel measurement capabilities via a new "Boottime" patch...

how does this differ from initcall_debug?

We already have initcall_debug, which bootgraph.pl and now my version of bootchart (github.com/sofar/bootchart - to be merged into systemd) parses and provides quite a lot of information, and is hardware neutral.

It's unclear to me if this is a worthwhile addition - focussing on creating graphable data for bootgraph.pl seems a mistake to me - I'd much rather see a hardware neutral resource profiler (why this needs to be ARM specific is a mystery to me) that spits out detailed resource consumption numbers, and can be parsed by many tools, not just bootgraph.pl...

Anyway, it's a shame this is ARM only, as it prevents me to include the output data as part of the graphs that my bootchart creates, as I don't have access to ARM hardware currently.

merging bootchart into systemd...

Originally Posted by Teho

Will it be integrated to systemd-analyze and replace the current tools and is there any chance of getting rid of the Python dependencies in the process?

it's a drop-in replacement for some of the functionality, and in the long term it will migrate the functionality of systemd-analyze into the graph output of bootchart. It's a nice addition to bootchart itself to include CGROUP information and it will help make better graph ordering of processes.

I'm not a fan of the python usage myself - hence the original reason I wrote a clean bootchart in C entirely ;^)

So yeah, ultimately you will have more data with less dependencies. Of course, you'll need a browser or SVG display utility to see the bootcharts 8^)

Waste of time. You can already do that with systemd and time the kernel and initramfs seperatly.

Looking at the code it seems to do quite a bit more than what systemd currently does, even from initramfs..

It does duplicate some of the bootgraph.pl/bootchart code that handles initcall_debug. But there's some CPU usage profiling that is at least new, although I can't establish the usefulness of it since it's ARM only....